A textbook of human physiology / translated from [the] 6th German edition by W. Stirling.

  • Landois, Leonard
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: A textbook of human physiology / translated from [the] 6th German edition by W. Stirling. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

    72/980 page 20
    Since average normal bloc J yields the tint of the standard at 100 degrees of dilution, the immber of degrees of dilution necessary to obtain the same tint with a given specimen of blood is the percentage proportion of the hivmoglobin contained in it, compared to the normal. For instance, the 20 cubic millimetres of blood from a jiatient with ane- mia gave the standard tint of 30 degrees of dilution. Heuce it contained only 30 per cent, of the normal quantity of hajuioglobin. By ascertaining with the haiuia- cytometer the corpuscular richness of tlie blood, we are able to compare tlic two. A fraction, of which the numerator is tiie percentage of liit'uioglobin, and the denominator the percentage of corpuscles, gives at once the average value per cor- puscle. Thus the blood mentioned above containing 30 per cent, of hainioglobin, contained 60 per cent, of corpuscles; hence the average value of each corpuscle was or ^ of the normal. A'ariations in the amount of hemoglobin may be re- corded on the same chart as that employed for the corpuscles. The instrument is only expected to yield approximate results, accurate within 2 or 3 per cent. It has, however, been found of much utility in clinical observation.] (e) FleiBchPs Hsemometer.—For clinical purposes this instrument (tig. 15) is useful. A cylinder G, of two compartments n and n', rests on a metallic table. Both com])artments are filled with water, but in one (a) is placed a known quantity of blood measured in a measuring-tube of known capacity*. The red coloiir of the solution of hiemo- globin thus obtained is compared witli a red wedge of glass (K), which is moved by means of a wheel (R and T) under the other compartment {a') until the two colours are identical. The illuniina- ation of the dilute blood solution and the red glass wedge is done from below bj' lamp light reflected from the white reflecting surface (S). The frame in which the red glass wedge is fixed bears numbers, and when the colour is iden- tical in the two compartments a and a\ the percentage of hajmoglobiii as com- pared with normal blood can be read off directly. Suppose it to be 80 on the scale, then the blood examined contains 80 per cent, of the ha-moglobin of normal blood. The amount of hiymoglobin in Fig. 14. Ciowers' ha;moglobinometer. A, pipette bottle for distilled water ; B, capillary pipette ; C, graduated tube ; D, tube with standard dilution ; F, lancet for pricking the finger. man is 1377 per cent,, in the woman 1259 per cent., during l)regnancy 9 to 12 per cent {Prepej^). According to lieichtenstern, Hb is in greatest amount in the blood of a newly-born infant, but after ten weeks the excess disappears. Be- tween six months and five years it is smallest in amount; it reaches its second Jiighest maximum between twenty-one and forty-five, and then sinks again. From Fleischl's hajmometer. K, red coloured wedge of glass moved by R; G, mixing vessel with two compartments a and a'; M, table with hole to read ott the percentage of haemoglobin on the scale P; T, to move K ; S, mirror of plaster of Paris.
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